Stereoscopic image display apparatus

Abstract

A stereoscopic image display apparatus including: an optical device having an n (n≧2) number of regions provided corresponding to the n number of parallax images, respectively, each region being capable of diffusing a coherent light beam; an irradiation unit to irradiate the optical device with a coherent light beam to scan the n number of the regions; a spatial light modulator that is illuminated with a coherent light beam incident on each of positions of the optical device and then diffused, to generate a modulated image corresponding to each of the n number of regions, in sync with the scanning of the n number of regions with the coherent light beam; and a projection optical system to project the n number of parallax images generated by the modulated image onto one plane to superimpose the parallax images on one another on the one plane at different angles.

The invention claimed is: 
     
       1. A stereoscopic image display apparatus comprising:
 an optical device that comprises a diffusing surface, the diffusing surface having an n (n being an integer of 2 or more) number of regions provided corresponding to the n number of parallax images, respectively, each region being capable of diffusing an incident coherent light beam; 
 an irradiation unit to irradiate the optical device with a coherent light beam to repeatedly and sequentially scan the n number of the regions with the coherent light beam; 
 a spatial light modulator that is illuminated with a coherent light beam incident on each of positions of the optical device and then diffused, to generate a modulated image corresponding to a scanning region among the n number of the regions; and 
 a projection optical system to project the n number of the parallax images generated by the modulated image onto one plane so that the parallax images are superimposed on one another on the one plane at different angles. 
 
     
     
       2. The stereoscopic image display apparatus of  claim 1 , wherein the projection optical system comprises a diffusing member that is disposed on the one plane to diffuse a coherent light beam corresponding to the modulated image. 
     
     
       3. The stereoscopic image display apparatus of  claim 2 , wherein diffusion characteristics of the diffusing member are different between one direction and another direction. 
     
     
       4. The stereoscopic image display apparatus of  claim 3 , wherein the diffusing member has different diffusion characteristics in a direction perpendicular to a horizontal direction in which horizontally adjacent pixels of a stereoscopic image viewable on the one plane are aligned, than in the horizontal direction. 
     
     
       5. The stereoscopic image display apparatus of  claim 1  further comprising a condensing optical system that converges the n number of the parallax images generated from the modulated image onto respective regions of an optical component disposed on the projection optical system. 
     
     
       6. The stereoscopic image display apparatus of  claim 1 , wherein the optical device is a hologram recording medium, the n number of the regions being n number of rectangular regions each extending in one direction of the hologram recording medium and having an interference fringe formed therein for diffracting a coherent light beam. 
     
     
       7. The stereoscopic image display apparatus of  claim 6 , wherein the n number of the rectangular regions are arranged so that a longitudinal direction of each rectangular region is perpendicular to a horizontal direction of the diffusing surface. 
     
     
       8. The stereoscopic image display apparatus of  claim 6 , wherein the n number of the rectangular regions are arranged so that neighboring rectangular regions are contacted. 
     
     
       9. The stereoscopic image display apparatus of  claim 6 , wherein the irradiation unit sequentially scans the n number of the rectangular regions with a coherent light beam in a longitudinal direction of each rectangular region; and
 while the irradiation unit is scanning one of the rectangular regions with a coherent light beam, the spatial light modulator continuously generates a modulated image corresponding to the one rectangular region. 
 
     
     
       10. The stereoscopic image display apparatus of  claim 1  further comprising a position detector that detects a viewer's position, wherein the irradiation unit scans only part of the n number of the regions with a coherent light beam so that a parallax image is viewed at the viewer's position detected by the position detector. 
     
     
       11. The stereoscopic image display apparatus of  claim 10 , wherein the position detector detects a viewer's view direction. 
     
     
       12. The stereoscopic image display apparatus of  claim 1 , wherein the irradiation unit comprises:
 a light source to emit a coherent light beam; and 
 a scanning device to adjust a reflection angle of the coherent light beam emitted from the light source and to scan the optical device with a reflected coherent light beam. 
 
     
     
       13. The stereoscopic image display apparatus of  claim 12 , wherein the light source comprises a plurality of light sources that emit a plurality of coherent light beams having different wavelength ranges, the n number of the regions of the optical device being scanned with coherent light beams from the respective light sources that correspond to the n number of the regions.